Thermoluminescence and microwave induced thermoluminescence fading of rare-earth-doped barium titanate ceramics

The effect of microwave exposure on thermoluminescence (TL) of rare-earth-doped BaTiO3 ceramic phosphors was investigated as a method for microwave dosimetry. Following exposure to 60Co gamma radiation, phosphors exhibited a TL glow curve with two peaks. The low temperature glow peak faded rapidly, but the high temperature glow peak was relatively stable with more than 50% of the initial response remaining after 48 h. The phosphors were linear in TL response over an exposure range of 103 to 105 R. Within-batch variation in TL response was insignificant for all phosphors except BaTiO3:Ce. Readouts from three batches of BaTiO3:Dy showed reproducible glow curve structure but significant differences in glow curve area. All phosphors except BaTiO3:Nd showed statistically significant TL fading following exposure to 100 mW/cm2 or more of microwaves. Fading increased with increasing microwave power density. Results of these studies show that rare-earth-doped BaTiO3 ceramics can potentially be utilized as microwave dosimeters if their sensitivity, stability and reproducibility are improved. (author)